Case Studies

UTE MPX - Pecém Power Plant – Pecém, CE – Brazil

Client: Brasfond Fundações Especiais S/A.The project for construction of a coal power plant included the excavation of 6 areas of 3000m2 and 1270 piles of 1000mm diameter with depths ranging from 10 to 18m. A 4m steel casing placed to start the excavation. The operation involved 3 drilling rigs and 2 auxiliary cranes thus resulting in a daily average production of 15 piles. With a wide available area it was quite easy to assemble the ideal slurry plants, 2 in total, used PolyMud® as a main all purpose stabilizer. The job was executed in a zone of tourism and beaches and ecologically protected environment with frequent local inspections to ensure the enforcement of the Brazilian environmental laws. The G3 System® was approved for application on site after tested locally.

The Challenges

All Piles integrity screened through cross hole testing

Main Contractor demanded 12 pile production per day.

The Main contractor specified bottom pile sampled sand contents to be lowered than 3%

All Piles had a 1 to 3 meters sockets bored on weathered rock (GNEISS) which lifts up solids in slurry and keeps it in suspension due to its fine granulometry.

Slurry de sanding cycle periods had to be below 15 minute to keep production requirements

Brazilian Environmental agency restrictive rules and constant monitoring of project development to ensure the protection of the environment as a touristic target area

Project defined 7 pile static load tests.

Benefits

GEO’s G3 System® technology was selected due to the vicinity of a very sensitive ecological reserve and all the environmental concerns involved.

Quality

Quality standards for pile integrity upheld through thigh quality screening. As a result the average sand content values registered at pile bottom ranged from 0,5 to 1%, prior to concrete pouring. Cross-hole testing confirmed good pile integrity. The load tests reached 720 tons values much higher than the 360 ton work load capacity required still without mobilizing end bearing capacity.

Production

it was possible to keep the high and demanding production rates and quality standards with and occasional usage of SuperDSand® to reset the system to 1,00 gr./cm3.

The G3 system® technology kept the working areas clean throughout the entire project guaranteeing a high production rates when compared to bentonite or steel casing. Avoiding the traditional mechanical means to separate sand from the fluid reinforcement cages were set in place upon pile completion reducing the pile execution cycle time. All concrete over breaks registered values under 10%.

With the application of PolyMud we observed:

Clean working areas without spillage to the surroundings.

Higher production rates when compared to bentonite or steel casing

Very low sand content values- Typically ranging from 0,50% to 1%

Concrete over breaks under 10%

Disposal of the slurry after treatment with no impact to the environment

Static pile Load testing met all specifications

Excavated spoils were transported dry outside the project area

Brazilian environmental agency after testing allowed project to go ahead using the G3 System

Change of method from recoverable full casing to PolyMud/G3® System triples production